Nurse Teaching: Side Effects of Zanaflex

Patient/caregiver was educated on the side-effects of using Zanaflex as follows:

  1. General allergic reactions: Zanaflex use can result in general allergic reactions, such as, skin rashes, hives, and itching. Some patients can present with symptoms of severe allergic and anaphylactic response with zanaflex, such as, difficulty breathing, swelling of face, lips, throat, and tongue, with consequent difficulty breathing. Seek emergency medical help for such findings, especially with difficulty breathing, for any appropriate measures to be considered.
  2. Genitourinary side-effects: Zanaflex intake, by some unknown mechanism, can induce bladder irritation and increase risk for urinary tract infection. Individuals with history of bladder disorders, retention of urine, and frequent urinary tract infections must be aware of this side-effect, as zanaflex can add further to their risk for UTIs.
  3. Withdrawal: Individuals on sudden withdrawal from zanaflex, especially after prolonged use or use in high doses, can present with unpleasant withdrawal symptoms, such as, hypertension, tachycardia, exacerbation of anxiety, agitation, sleep disturbances, mania, rebound spasticity, bad muscle spasms, and seizures. Discontinuation on zanaflex use must be slow and gradual, using tapering doses, and only on your physician recommendation.
  4. Gastrointestinal side-effects: This medication can induce some nausea, vomiting, and stomach upset with self-limiting diarrhea, especially when taken on empty stomach. Taking the medication with a glass of water and some food or snack can help avoid these unpleasant gastrointestinal symptoms. Observe compliance with fluid, electrolyte, and nutrition intake, as recommended. If stomach upset, vomiting, and diarrhea are uncontrolled, report to your physician immediately for further recommendations. Zanaflex can also induce extreme dry mouth and constipation. Sucking on a sugar free hard candy can help with symptomatic relief of dry mouth. Proper hydration measures and compliance with daily fluid intake recommendations can help with relief from constipation. If you experience any further bothersome constipation, report it to your physician for a recommendation on laxative/stool softener use. Observing compliance with fiber intake recommendations in the diet can also help with preventing episodes of constipation with the medication. Zanaflex can rarely induce hepatic dysfunction and liver toxicity, leading to fatal liver failure. Individuals can present with symptoms of liver failure and jaundice, such as, yellowing of skin and eyes, dark yellow colored urine, itching of skin, upper right abdominal pain, abdominal distension, nausea and vomiting, confusion and disorientation, fluid retention in the body with swelling & acute weight gain, and compromised appetite. Also, liver is the site of synthesis for blood clotting factors. In liver dysfunction, synthesis of clotting factors can be impaired leading to episodes of bleeding from the gastrointestinal and urinary tracts and bleeding episodes in the skin. Individuals with liver dysfunction can present with severe hemorrhages into the skin even from minor bruising, red tinged urine, fresh blood in the stool, or black tarry stool from partially digested blood in the intestines. Report any of these bleeding episodes to your physician immediately for appropriate measures to be considered.
  5. Cardiovascular side-effects: Zanaflex, especially when taken in high doses, carries the risk of depressing the cardiovascular center in the brain, which regulates the heart rate and blood pressure. Consequently, intake of zanaflex can result in low heart rate and blood pressure. This risk with zanaflex can be even high when it is taken along with any other products and medications causing hypotension and bradycardia, such as, antihypertensives, antidepressants, antianxiety medications, and sedatives. Hypotension and bradycardia, secondary to zanaflex intake, can contribute to the confusion and dizziness, thus significantly increasing the risk for fall and accidents.
  6. Central nervous system side-effects: Zanaflex use can result in episodes of confusion, dizziness, and light-headedness. This risk with zanaflex can be even high when it is taken along with any other products and medications causing central nervous depression, such as, alcohol, opioid pain medications, antidepressants, antianxiety medications, and sedatives. Watching closely for therapeutic response and gradually changing the dose, to help optimum control of your symptoms, can contribute to controlling/reducing the risk for drowsiness and dizziness due to the medication. Zanaflex use, especially in individuals with history of mood disorders, can occasionally result in exacerbation of anxiety and depressive symptoms, changes in behavior, hallucinations, and compromised sexual drive.
  7. Respiratory depression: Zanaflex, especially when taken in high doses, can lead to depression of respiratory center in the brain and consequently cause exacerbation of SOB, and difficult breathing. This risk with zanaflex can be even high when it is taken along with any other products and medications causing central nervous depression, such as, alcohol, antidepressants, antianxiety medications, and sedatives. Individuals with history of breathing disorders, such as, asthma, emphysema, and COPD, are at increased risk for presentation with severe debility due to respiratory arrest from zanaflex intake.